Catalyst composition and method for preparing the same

ABSTRACT

The present invention relates to a catalyst composition for the polymerisation of olefins comprising a support containing a single site catalyst component, a catalyst activator and a modifier wherein the modifier is the product of reacting an aluminum compound of general formula AI(R1, R2, R3) with an amine compound of general formula N(R4, R5, R6). The catalyst composition reduces fouling and/or sheeting when used to catalyse the polymerisation of olefins. The present invention also relates to a method for the polymerisation of olefins using the catalyst composition of the invention.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 371 of International Application No.PCT/EP2012/005298, filed Dec. 20, 2012, which claims priority toEuropean Application No. 11010262.1, filed Dec. 28, 2011, both of whichare hereby incorporated by reference in its entirety.

The present invention relates to a catalyst composition for thepolymerisation of olefins comprising a support containing a single sitecatalyst component, a catalyst activator and a modifier. The presentinvention further relates to a method for preparing such a catalyst. Thepresent invention further relates to a method for the polymerisation ofolefins.

Olefin polymerisation processes utilizing single site catalystcompositions allow a diverse array of new polymers to be produced whichare useful in a wide variety of applications and products. Single-sitecatalysts include metallocene catalysts and non-metallocene catalysts.Metallocene catalysts generally are complexes with one or twocyclopentadienyl groups or cyclopentadienyl derivatives which are bondedto a transition metal atom, for example a transition metal selected fromthe group consisting of lanthanides and metals from group 3, 4, 5 or 6of the Periodic System of Elements. Similar functioning structures suchas phospholes may be used as well. Single-site catalysts may also haveother stabilizing ligands such as cyclooctatetradienyl, imides, phenoxyimines, amines and the like. Examples of typical single-site catalystsinclude but are not limited to bridged or unbridged metallocenes,mono-cyclopentadienyl containing complexes, late transition metalcontaining complexes and metal complexes with one or more ofphosphinimine cyclooctatetraendiyl, imides, phenoxy imines, aminesstabilizing ligands.

The skilled person is well aware of all the several types of single sitecatalysts.

A problem associated with the use of supported single site catalystsystems, in particular based on metallocene catalyst components, istheir tendency to cause fouling and/or sheeting in gas phase and slurrypolymerisation processes. Fouling on the walls of the reactor and/orreactor components results in many serious problems including poor heattransfer, particle morphology, and undesirable reactor shut-down. Also,fines may be formed.

With fouling as used herein is meant the sticking or formation ofmaterial, for example in the form of particles, on the inside walland/or other components on the inside of the reactor. While not wishingto be bound by it, the present inventors believe that reactor wallfouling, which occurs during polymerisation, is due to several factors.First, residual solvent may remain in the pores of the catalyst supportmaterial employed at the stage after placement of the catalyst onto thecarrier. The residual solvent prevents the catalyst system from securelyanchoring itself onto the carrier or into the pores of the carrier. Thuswhen the supported catalyst is added to the reaction polymerisationvessel, the catalyst disassociates from the support, and migrates to thereactor walls where monomer can polymerize therefrom and cause fouling.Secondly, when alumoxane, such as methyl alumoxane (MAO) is used ascocatalyst in the polymerisation at temperatures about or greater than40° C., the alumoxane may dissolve and extract the metallocene catalystfrom the support forming a soluble catalyst in the polymerisationmedium. This soluble catalyst easily deposits polymer onto the reactorwalls and/or generates very small particles of low bulk density whichare undesirable in a commercial reactor. Reactor fouling due to the useof alumoxane is of particular importance for catalyst compositions basedon metallocene catalyst components which require relatively high amountsof catalyst activator for their activation.

With sheeting as used herein is meant the formation of a sheet, e.g. athin layer, of polymer material on the inside wall and/or othercomponents on the inside of the reactor.

Various methods for reducing fouling and/or sheeting of a single-sitecatalyst system have been disclosed in the art. U.S. Pat. No. 5,283,218discloses the prepolymerisation of a metallocene catalyst. U.S. Pat. No.5,332,706 and U.S. Pat. No. 5,473,028 report to form a catalyst by“incipient impregnation”. U.S. Pat. Nos. 5,427,991 and 5,643,847disclose the use of tethered non-coordinating anionic activators intosupports. U.S. Pat. No. 5,492,975 discloses polymer bound metallocenecatalyst systems. U.S. Pat. No. 5,661,095 supported a metallocenecatalyst on a copolymer of an olefin and an unsaturated silane. WO97/06186 discloses a technique to remove impurities after formation ofthe metallocene catalyst. WO 97/27224 relates to support catalysts inthe presence of an unsaturated organic compound having at least oneterminal double bond. WO 97/14721 discloses to introduce an inerthydrocarbon to the reactor in order to reduce fines that can causesheeting.

U.S. Pat. No. 5,627,243 uses a new type of distributor plate forfluidized bed gas phase reactors. WO 96/08520 discusses eliminating ascavenger into the reactor. U.S. Pat. No. 5,461,123 discloses to applysound waves in order to reduce sheeting. U.S. Pat. No. 5,066,736 and EP10549252 disclose to introduce an activity retarder to reduceagglomerates. U.S. Pat. No. 5,610,244 feeds make-up monomer directlyinto the reactor to avoid fouling. EP 0453116 discloses the introductionof antistatic agents to the reactor for reducing the amount of sheetsand agglomerates. U.S. Pat. No. 4,012,574 teaches adding asurface-active compound, such as a perfluorocarbon group to the reactorto reduce fouling. WO 96/11961 discloses a supported catalyst systemhaving an antistatic component for reducing fouling and sheeting inseveral polymerisation processes. U.S. Pat. No. 5,026,795 teaches theaddition of an antistatic agent with a liquid carrier to thepolymerisation zone in the reactor. WO 97/46599 discloses to utilizesoluble metallocene catalysts that are fed into a lean zone in apolymerisation reactor with antifoulants or antistatic agents such asATMER 163 (available from ICI Specialty Chemicals, Baltimore, Md.). EP811638 discusses using a metallocene catalyst and an activatingcocatalyst in a polymerisation process in the presence of nitrogencontaining antistatic agent.

There are various other known methods for improving operabilityincluding coating the polymerisation equipment, injecting various agentsinto the reactor, controlling the polymerisation rate, particularly onstart-up, and reconfiguring the reactor design.

WO 96/11960 discloses a catalyst system prepared by combining in asuitable solvent a support material, a metallocene catalyst component,an activator and a surface modifier. WO 96/11960 defines the surfacemodifier as any organic compound containing at least one electron richheteroatom from Groups IV, V and/or VI in addition to a hydrocarbylmoiety. Typical of such heteroatoms are silicon, oxygen, nitrogen,phosphorus, and sulfur. The surface modifier may also contain at leastone active hydrogen atom attached to the heteroatom. The hydrocarbylmoiety should have a molecular weight sufficient to give it solubilityin typical hydrocarbon solvents such as cyclic aliphatic or aromatichydrocarbons. The surface modifier can be represented by the formula,R_(m)XH_(n) where R may be a branched or straight chain hydrocarbylgroup or substituted hydrocarbyl group or groups having one or morecarbon atoms and where X is at least one heteroatom, which can be O, N,P or S atoms or a combination thereof and H is an active hydrogen and nis such that the compound has no net charge. As an example of thesurface modifier WO96/11960 discloses Kemamine AS-990 and Atmer 163,both being alkoxylated tertiary amines. The catalyst compositions of WO95/11960 reduce fouling and sheeting in a gas phase or slurrypolymerisation process, in addition to that the catalyst composition hasbetter flow properties which facilitate its delivery into the reactorand. Finally this catalyst composition results in a high bulk densitypolymer product having improved physical properties.

WO 2006/130953 is directed to the problem of fouling and/or sheetingduring the polymerisation of olefins. This patent application disclosesthat aluminum alkyls are often used as scavengers for olefinpolymerisation, but that an excess amount of scavenger will deactivatethe single-site catalyst. In addition to that antistatic agents such asamines or hydroxylated amines (which are well known antistatic agents)may deactivate single site catalysts by blocking the active catalyticcentres. WO2006/130953 discloses a process for olefin polymerisationwhich prevents reactor fouling and/or sheeting and simultaneouslyprovides a sufficient productivity of the catalytic system used. Theprocess of WO2006/130953 comprises the steps of (i) introducing at leastone olefin, at least one polymerisation catalyst, and at least onecocatalyst aid, and optionally a scavenger, into a polymerisationreactor, and (ii) polymerizing the olefin, wherein the cocatalyst aid isa reaction product prepared separately prior to the introduction intothe reactor by reacting at least one metal alkyl compound of group IIAor IIIA of the periodic system of elements and at least one compound (A)of the formula R_(m)XR′_(n) wherein R is a branched, straight, orcyclic, substituted or unsubstituted, hydrocarbon group having 1 to 50carbon atoms, R′ is hydrogen or any functional group with at least oneactive hydrogen, X is at least one heteroatom selected from the group ofO, N, P or S or a combination thereof, and wherein n and m are each atleast 1 and are such that the formula has no net charge wherein theratio of the metal of the metal alkyl compound and X of compound (A) isabout 1:2 to about 10:1. As an example of the cocatalyst aid WO2006/130953 discloses the reaction product of the reaction betweenaluminumalkyls such as triisobutylaluminum and antistatic agents such asC₁₈H₃₇NH₂. According to WO 2006/130953 it is essential that the cocatalyst aid is prepared separately prior to being introduced into thepolymerisation reaction. The mere addition of an antistatic agent (suchas C₁₈H₃₇NH₂) and a scavenger (such as aluminumalkyls) separately intothe polymerisation reactor should be avoided. According to the inventionof WO 2006/130953 the problems with regard to scavenger capability aswell as antistatic capability are overcome.

Reactions between amine and aluminum alkyls as disclosed in WO2006/130953 have been reported before. It is believed that the firststep is a ligand addition between the aluminum alkyl and the amine. Thealkyl elimination could occur at elevated temperature. (J. J. Eisch,page 555, Chapter 6, vol. 1, Comprehensive Organometallic Chemistry,Edited by Geoffrey Wilkinson, Gordon A. Stone and Edward W. Abel, byPergamon Press.)

There exists a need for a further improved catalyst composition thatallows a process for the polymerisation of olefins wherein foulingand/or sheeting during the process is reduced to a minimum, wherein thecatalyst has high catalyst productivity, good flow properties and isrelatively easy to prepare and wherein the obtained polyolefin has ahigh bulk density.

The present inventors have surprisingly found that such a process may beperformed by employing a catalyst composition for the polymerisation ofolefins comprising a support containing a single site catalystcomponent, a catalyst activator and a modifier wherein the modifier isthe product of reacting an aluminum compound of general formula (1)

with an amine compound of general formula (2)

wherein

-   -   R1 is hydrogen or a branched or straight, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R2 and R3 are the same or different and selected from branched        or straight, substituted or unsubstituted hydrocarbon groups        having 1-30 carbon atoms and    -   R4 is hydrogen or a functional group with at least one active        hydrogen    -   R5 is hydrogen or a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R6 is a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms.

An important aspect of the invention is that the single site catalystcomponent, the catalyst activator and the modifier are contained by thesupport. In other words, in the catalyst composition of the invention,the single site catalyst component, the catalyst activator and themodifier are all present on the support, obviating the need for separateaddition of the modifier and of the support containing the single sitecatalyst component and the activator.

The catalyst composition of the invention may contain from 0.01-5 wt %,preferably from 0.5-3 wt %, more preferably from 0.3-2 wt % of themodifier, based on the catalyst composition.

In a preferred embodiment of the invention the amounts of aluminumcompound and amine compound are selected such that in the modifier themolar ratio of Al to N is in the range of 1:3 to 5:1, preferably 1:2 to3:1, more preferably 1:1.5 to 1.5:1. The present inventors found thatwithin this range a good combination of technical effects of the presentinvention can be obtained. If the molar ratio of Al to N is below 1:3then fouling and/or sheeting may occur, whereas if the molar ratio of Alto N is above 5:1 catalyst productivity decreases, i.e. the amount ofpolymer produced per gram of catalyst decreases. The most preferredmolar ratio is 1:1.

In the compound of general formula (2), R4 is a hydrogen or a functionalgroup with at least one active hydrogen, R5 is hydrogen or a branched,straight or cyclic, substituted or unsubstituted hydrocarbon grouphaving 1-30 carbon atoms, R6 is a branched, straight or cyclic,substituted or unsubstituted hydrocarbon group having 1-30 carbon atoms(carbon atoms of the substituents included). The branched, straight orcyclic, substituted or unsubstituted hydrocarbon group having 1-30carbon atoms is preferably an alkyl group having 1-30 carbon atoms, forexample an alkyl group having 1-30 carbon atoms, for example a straight,branched or cyclic alkyl, an aralkyl group having 1-30 carbon atoms oran alkaryl group having 1-30 carbon atoms.

The amine compound used in the reaction to prepare the modifier may be asingle amine compound or a mixture of two or more different aminecompounds.

The amine compound used for preparing the modifier of the presentinvention preferably has a hydrocarbon group of at least eight carbonatoms, more preferably at least twelve carbon atoms, for example analkyl group of 1 to fifteen carbon atoms. The amine compound may be aprimary, secondary or tertiary amine. The amine compound is preferably aprimary amine.

In an embodiment of the present invention the amine compound is selectedfrom the group consisting of octadecylamine, ethylhexylamine,cyclohexylamine, bis(4-aminocyclohexyl)methane, hexamethylenediamine,1,3-benzenedimethanamine,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and6-amino-1,3-dimethyluracil.

The aluminum compound used in the reaction to prepare the modifier maybe a single aluminum compound or a mixture of two or more differentaluminum compounds. R1, R2 and R3 may each independently stand for abranched or straight, substituted or unsubstituted hydrocarbon grouphaving 1-30 carbon atoms, for example may each independently stand foran alkyl, preferably R1, R2 and R3 all stand for an alkyl, morepreferably R1, R2 and R3 are the same.

The aluminum compound of the present invention is preferably atrialkylaluminum (R1=R2=R3=alkyl or a dialkylaluminumhydride(R1=hydrogen, R2=R3=alkyl).

In an embodiment of the present invention the aluminum compound isselected from the group consisting of tri-methylaluminum,tri-ethylaluminum, tri-propylaluminum, tri-butylaluminum,tri-isopropylaluminum tri-isobutylaluminum, or di-methylaluminumhydride,di-ethylaluminumhydride, di-propylaluminumhydride,di-butylaluminumhydride, di-isopropylaluminumhydride,di-isobutylaluminumhydride. These materials are readily available andhave good reactivity with amines.

An alkyl as used herein will be understood by the skilled person asmeaning a hydrocarbon group that contains only carbon and hydrogen atomsand is derived from alkanes such as methane, ethane, propane, butane,pentane, hexane etc. The alkyl may be branched, straight or cyclic.Preferably R1, R2 and R3 may each independently stand for a straight orbranched alkyl.

In a preferred embodiment the aluminum compound is a trialkylaluminumand the amine compound is a primary amine, preferably the aluminiumcompound is selected from the group consisting of octadecylamine,ethylhexylamine, cyclohexylamine, bis(4-aminocyclohexyl)methane,hexamethylenediamine, 1,3-benzenedimethanamine,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and6-amino-1,3-dimethyluracil.

The catalyst component of the present invention is preferably ametallocene catalyst of the general formula I below

wherein:

-   -   M is a transition metal selected from the group consisting of        lanthanides and metals from group 3, 4, 5 or 6 of the Periodic        System of Elements; M is preferably selected from the group        consisting of Ti, Zr and Hf with Zr being most preferred.    -   Q is an anionic ligand to M,    -   k represents the number of anionic ligands Q and equals the        valence of M minus two divided by the valence of the anionic Q        ligand    -   R is a hydrocarbon bridging group, such as alkyl. R preferably        contains at least one sp2-hybridised carbon atom that is bonded        to the indenyl group at the 2-position.    -   Z and X are substituents.

In another preferred embodiment the metallocene catalyst is of thegeneral formula II below

wherein:

-   -   M is a transition metal selected from the group consisting of        lanthanides and metals from group 3, 4, 5 or 6 of the Periodic        System of Elements; M is preferably selected from the group        consisting of Ti, Zr and Hf with Zr being most preferred.    -   Q is an anionic ligand to M,    -   k represents the number of anionic ligands Q and equals the        valence of M minus two divided by the valence of the anionic Q        ligand    -   R is a hydrocarbon bridging group, such as alkyl. R preferably        contains at least one sp2-hybridised carbon atom that is bonded        to the indenyl group at the 2-position.    -   Z and X are substituents.

Bridging group R in the metallocene catalysts of general formula's I andII above preferably contains at least one aryl group. For example, thearyl group may be a monoaryl group such as phenylene or naphthalene or abiaryl group, such as biphenylidene or binaphthyl. Preferably thebridging group R stands for an aryl group, preferably R stands for aphenylene or biphenylidene group. The bridging group R is connected tothe indenyl groups via a sp2 hybridised carbon atom, for example aphenylene group may be connected via the 1 and the 2 position, abiphenylene group may be connected via the 2 and 2′-position, anaphthalene group may be connected via the 2 and 3-position, a binapthylgroup may be connected via the 2 and 2′-position. Preferably R standsfor a phenylene group that is connected to the indenyl groups via the 1and the 2 position. R may be 2,2′-biphenylene.

The substituents X in formulas I and II above may each separately behydrogen or a hydrocarbon group with 1-20 carbon atoms (e.g. alkyl,aryl, aryl alkyl). Examples of alkyl groups are methyl, ethyl, propyl,butyl, hexyl and decyl. Examples of aryl groups are phenyl, mesityl,tolyl and cumenyl. Examples of aryl alkyl groups are benzyl,pentamethylbenzyl, xylyl, styryl and trityl. Examples of othersubstituents are halides, such as chloride, bromide, fluoride andiodide, methoxy, ethoxy and phenoxy. Also, two adjacent hydrocarbonradicals may be connected with each other in a ring system. X may alsobe a substituent which instead of or in addition to carbon and/orhydrogen may comprise one or more heteroatoms from group 14, 15 or 16 ofthe Periodic System of Elements. Examples of such a heteroatomcontaining substituents are alkylsulphides (like MeS—, PhS—,n-butyl-S—), amines (like Me2N—, n-butyl-N—), Si or B containing groups(like Me3Si— or Et2B—) or P— containing groups (like Me2P— or Ph2P—).

Preferably the X substituents are hydrogen.

The substituents Z in formulas I and II above may each separately be asubstituent as defined above for substituent X, Z1 and Z2 substituentscan together with the X1 and X4 substituents form a second bridge thatconnects the indenyl group with the cyclopentadienyl group in theindenyl compound.

Examples of metallocene catalysts for use in the present invention are[ortho-bis(4-phenyl-2-indenyl)-benzene]zirconiumdichloride,[ortho-bis(5-phenyl-2-indenyl)-benzene]zirconiumdichloride,[ortho-bis(2-indenyl)benzene]zirconiumdichloride,[ortho-bis(2-indenyl)benzene]hafniumdichloride,[ortho-bis(1-methyl-2-indenyl)-benzene]zirconiumdichloride,[2.2′-(1.2-phenyldiyl)-1.1′-dimethylsilyl-bis(indene)]zirconiumdichloride,[2,2′-(1,2-phenyldiyl)-1,1′-diphenylsilyl-bis(indene)]zirconiumdichloride,[2,2′-(1.2-phenyldiyl)-1.1′-(1.2-ethanediyl)-bis(indene)]zirconiumdichloride,[2.2′-bis(2-indenyl)biphenyl]zirconiumdichloride and[2,2′-bis(2-indenyl)biphenyl]hafniumdichloride,

The metallocene catalyst component preferably contains zirconium asmetal group M. The zirconium amount in the catalyst composition ispreferably in the range of 0.02-1 wt %, preferably 0.15-0.30 wt % basedon the catalyst composition.

In a special embodiment, the invention relates to a catalyst compositionfor the polymerization of olefins comprising a support containing ametallocene catalyst, preferably biphenyl(2-indenyl)₂ZrCl₂,(methyl)aluminoxane or modified methylaluminoxane and a modifier,wherein the modifier is the product of reacting octadecylamine,2-ethylhexylamine or cyclohexylamine with triisobutylaluminum.

Preferably, the invention relates to a catalyst composition for thepolymerization of olefins comprising a support containing a single sitecatalyst component, preferably a metallocene catalyst, a catalystactivator, preferably an aluminoxane and a modifier wherein the modifieris the product of reacting an aluminum compound of general formula (1)

with an amine compound of general formula (2)

wherein

-   -   R1 is hydrogen or a branched or straight, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R2 and R3 are the same or different and selected from branched        or straight, substituted or unsubstituted hydrocarbon groups        having 1-30 carbon atoms and    -   R4 is hydrogen or a functional group with at least one active        hydrogen    -   R5 is hydrogen or a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R6 is a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,        wherein the catalyst composition is prepared by a method        comprising the steps of

a) preparing the modifier by reacting the aluminium compound of generalformula (1)

with the amine compound of general formula (2)

wherein R1, R2, R3, R4, R5 and R6 are as defined herein

b) activating the single site catalyst component by adding the catalystactivator to said single site catalyst component to obtain an activatedsingle site catalyst component

c) combining in a solvent a support material, the activated single sitecatalyst component obtained in step b) and the modifier obtained in stepa) and

d) optionally drying the reaction product obtained in step c)

The term “catalyst activator” as used herein is to be understood as anycompound which can activate the single-site catalyst so that it iscapable of polymerisation of monomers, in particular olefins. Preferablythe catalyst activator is an alumoxane, a perfluorophenylborane and/or aperfluorophenylborate, preferably alumoxane, more preferablymethylaluminoxane and/or modified methylaluminoxane.

The support in the catalyst composition of the present invention can bean organic or inorganic material and is preferably porous. Examples oforganic material are cross-linked or functionalized polystyrene, PVC,cross-linked polyethylene. Examples of inorganic material are silica,alumina, silica-alumina, inorganic chlorides such as MgCl₂, talc andzeolite. Mixtures of two or more of these supports may be used. Thepreferred particle size of the support is from 1 to 120 micrometers,preferably of from 20 to 80 micrometers and the preferred averageparticle size is from 40 to 50 micrometers.

The preferred support is silica. The pore volume of the support ispreferably of from 0.5 to 3 cm³/g. The preferred surface area of thesupport material is in the range of from 50 to 500 m²/g. The silica usedin this invention is preferably dehydrated prior to being used toprepare the catalyst composition.

In case of a zirconium catalyst component, the amount of zirconium basedon the support may for example be in the range from 0.05 to 3 wt %.

The catalyst composition according to the invention may further comprisea Ziegler-Natta and/or a chromium based catalyst component. Preferably,the invention relates to a catalyst composition comprising one catalystcomponent, more preferably wherein the one catalyst component is ametallocene catalyst. In a preferred embodiment of the invention, thecatalyst component is diphenyl(2-indenyl)₂ ZrCl₂.

The catalyst composition preferably has an aluminum content in the rangeof 3-20 wt %, preferably 7-12 wt % based on the catalyst composition.

The catalyst composition of the present invention may be prepared by amethod comprising the steps of

-   -   a) preparing a modifier by reacting an aluminum compound of        general formula (1)

with an amine compound of general formula (2)

-   -   b) activating a single site catalyst component by adding a        catalyst activator to said single site catalyst component,        preferably in an organic solvent such as toluene or xylene to        obtain an activated single site catalyst component    -   c) combining in a solvent a support material, the activated        single site catalyst component obtained in step b) and the        modifier obtained in step a)    -   d) optionally drying the reaction product obtained in step c)

wherein R1 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms,

R2 and R3 are the same or different and selected from branched orstraight, substituted or unsubstituted hydrocarbon groups having 1-30carbon atoms and

R4 is hydrogen or a functional group with at least one active hydrogen

R5 is hydrogen or a branched, straight or cyclic, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms,

R6 is a branched, straight or cyclic, substituted or unsubstitutedhydrocarbon group having 1-30 carbon atoms.

In a practical embodiment step c) may be carried out by adding theactivated single site catalyst, optionally including an organic solvent,to the support. The so obtained mixture may further react for at leastthirty minutes, preferably at least one hour at a temperature of between20° C. and 80° C., preferably between 40° C. and 60° C., after which themodifier obtained in step a) is added.

Step a) in the method for preparing the catalyst composition ispreferably carried out a temperature of 0° C.-50° C., more preferably ata temperature of 10° C. to 35° C.

The catalyst composition obtained after drying is a dry flowing powderwith particle size range of 1 to 300 microns, more preferably 5 to 90microns.

The catalyst composition of the invention is preferably stored under aninert atmosphere, such as nitrogen or argon.

The present invention further relates to a method for the polymerisationof olefins comprising contacting olefins with the catalyst compositionaccording to the invention under reaction conditions effective forforming a polyolefin. The polymerisation of olefins may be carried outin solution, slurry and gas-phase polymerisation process. Morepreferably in slurry and gas-phase process, in particular a condensedmode gas phase process.

The production processes of LDPE, HDPE and LLDPE are summarised inHandbook of Polyethylene by Andrew Peacock (2000; Dekker; ISBN0824795466) at pages 43-66.

The catalyst composition of the present invention may be used topolymerise or copolymerise olefins, such as for example ethylene,propylene, butylene, hexene and octene. Other monomers that can be(co)polymerized include conjugated and non-conjugated dienes such asbutadiene and isoprene, norbornene and styrene.

Preferably, the catalyst composition of the invention is used to producepolyethylene or an ethylene-alpha olefin copolymer, for example linearlow density polyethylene.

Preferably the catalyst composition of the present invention is used forthe polymerisation of ethylene to linear low density polyethylene(LLDPE). To that extent ethylene may be copolymerised with small amountsof copolymers, for example alpha-olefins having 3 to 10 carbon atoms.For example ethylene may be copolymerized with octene whenpolymerisation is carried out in a slurry phase and butene and/or hexenewhen polymerisation is carried out in the gas phase. Reaction conditionsand equipment to be employed for the polymerisation are known to theskilled person.

Any conventional ethylene (co)polymerization reaction may be employed toproduce polyethylene. Such conventional ethylene (co)polymerizationreactions include, but are not limited to, gas phase polymerizationprocess, slurry phase polymerization process, liquid phasepolymerization process, and combinations thereof using one or moreconventional reactors, e.g. fluidized bed gas phase reactors, loopreactors, stirred tank reactors, batch reactors in parallel, series,and/or any combinations thereof. In the alternative, the linear lowdensity polyethylene may be produced in a high pressure reactor. Forexample, the (linear low density) polyethylene according to the instantinvention may be produced via gas phase polymerization process in asingle gas phase reactor; however, the instant invention is not solimited, and any of the above polymerization processes may be employed.In one embodiment, the polymerization reactor may comprise of two ormore reactors in series, parallel, or combinations thereof. Preferably,the polymerization reactor is one reactor, e.g. a fluidized bed gasphase reactor. In another embodiment, the gas phase polymerizationreactor is a continuous polymerization reactor comprising one or morefeed streams. In the polymerization reactor, the one or more feedstreams are combined together, and the gas comprising ethylene andoptionally one or more comonomers, e.g. one or more alpha-olefins, areflowed or cycled continuously through the polymerization reactor by anysuitable means. The gas comprising ethylene and optionally one or morecomonomers, e.g. alpha-olefins having 3 to 10 carbon atoms, may be fedup through a distributor plate to fluidize the bed in a continuousfluidization process.

In production, the catalyst composition of the invention, ethylene,optionally alpha-olefins having 3 to 10 carbon atoms, hydrogen,optionally one or more inert gases and/or liquids, e.g. N₂, isopentane,and hexane, and optionally one or more continuity additive, e.g.ethoxylated stearyl amine or aluminum distearate or combinationsthereof, are continuously fed into a reactor, e.g. a fluidized bed gasphase reactor. Such fluidized bed gas phase reactor may be in fluidcommunication with one or more discharge tanks, surge tanks, purgetanks, and/or recycle compressors. The temperature in such reactor mayfor example be in the range of 70 to 115° C., preferably 75 to 110° C.,more preferably 75 to 100° C., and the pressure may be in the range of15 to 30 atm, preferably 17 to 26 atm. A distributor plate that may bepresent at the bottom of the polyethylene in the fluidized bed gas phasereactor provides a uniform flow of the upflowing monomer, comonomer, andinert gases stream. A mechanical agitator may also be provided toprovide contact between the solid particles and the comonomer gasstream. The fluidized bed, a vertical cylindrical reactor, may have abulb shape at the top to facilitate the reduction of gas velocity; thus,permitting the granular polyethylene to separate from the upflowinggases. The unreacted gases may then be cooled to remove the heat ofpolymerization, recompressed, and then recycled to the bottom of thereactor. The residual hydrocarbons may then be removed and thepolyethylene produced may be transported under N₂ to a purge bin. Also,moisture may be introduced to reduce the presence of any residualcatalyzed reactions with O₂ before the polyethylene is exposed tooxygen.

In the fluidized bed reactor, a monomer stream may be passed to apolymerization section. The fluidized bed reactor may include a reactionzone in fluid communication with a velocity reduction zone. The reactionzone includes a bed of growing polyethylene particles, formedpolyethylene particles and catalyst composition particles fluidized bythe continuous flow of polymerizable and modifying gaseous components inthe form of make-up feed and recycle fluid through the reaction zone.Preferably, the make-up feed includes ethylene and optionally one ormore alpha-olefins having 3 to 10 carbon atoms, and may also includecondensing agents as is known in the art and disclosed in, for example,U.S. Pat. Nos. 4,543,399, 5,405,922, and 5,462,999.

It is preferable that the ethylene is present in the reactor at apartial pressure at or greater than 160 psia (1100 kPa), or 190 psia(1300 kPa), or 200 psia (1380 kPa), or 210 psia (1450 kPa), or 220 psia(1515 kPa). The comonomer, e.g. one or more alpha-olefins having 3 to 10carbon atoms, if present in the polymerization reactor, is present atany level that will achieve the desired weight percent incorporation ofthe comonomer into the polyethylene. This may be expressed as a moleratio of comonomer to ethylene as described herein, which is the ratioof the gas concentration of comonomer moles in the cycle gas to the gasconcentration of ethylene moles in the cycle gas. In one embodiment ofthe inventive polyethylene composition production, the comonomer ispresent with ethylene in the cycle gas in a mole ratio range of from 0to 0.1 comonomer to 1 mole of ethylene, for example in a mole ratiorange of from 0 to 0.05, for example from 0 to 0.04, for example from 0to 0.03, for example from 0 to 0.02 comonomer to 1 mole of ethylene.

Hydrogen gas may also be added to the polymerization reactor(s). Forexample, the ratio of hydrogen to total ethylene monomer (ppm H₂/mol %ethylene) in the circulating gas stream may be in the range from 0 to60:1, for example from 0.10:1 to 50:1, for example from 0 to 35:1, forexample from 0 to 25:1, for example from 7:1 to 22:1.

The optimal amount of catalyst component to be used in thepolymerization can easily be determined by the person skilled in the artthrough routine experimentation. For example, the amount of catalystcomponent may be chosen such that the productivity is in the range from1500 to 10000 gram polyolefin per gram catalyst.

During the polymerisation small amounts of scavenger, such as aluminumalkyl may also be added to the reactor in order to prevent impurities inthe reactor from deactivating or poisoning the catalyst. Typicalscavengers include triisobutyl aluminum, trihexyl aluminum, triisopropylaluminum, triethylaluminum and trimethyl aluminum (TMA).

During the polymerisation of olefins a continuity aid agent (CAA) mayalso be added to the reactor. Said continuity aid agent is preparedseparately prior to introduction into the reactor by reacting:

-   -   at least one metal alkyl or metal alkyl hydride compound of a        metal from group IIA or IIIA of the periodic system of elements,        and    -   at least one compound of general formula R_(m)XR′_(n′)        wherein    -   R is a branched, straight, or cyclic, substituted or        unsubstituted hydrocarbon group having 1 to 50, preferably        10-40, carbon atoms,    -   R′ is hydrogen or a functional group with at least one active        hydrogen, for example an OH group    -   X is a heteroatom selected from the group of O, N, P or S,    -   n and m are each at least 1 and are such that the formula has no        net charge,    -   the molar ratio of the metal of the metal alkyl compound and X        is about 2:1 to about 10:1.

Preferably the continuity aid agent is the same or different as themodifier present in the composition according to the present inventionand is the product of reacting an aluminum compound of general formula(1)

with an amine compound of general formula (2)

wherein R1, R2, R3, R4, R5 and R6 are as defined herein:

-   -   R1 is hydrogen or a branched or straight, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R2 and R3 are the same or different and selected from branched        or straight, substituted or unsubstituted hydrocarbon groups        having 1-30 carbon atoms,    -   R4 is hydrogen or a functional group with at least one active        hydrogen    -   R5 is hydrogen or a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R6 is a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms.

The continuity aid agent is added to the reactor as a further processaid for reducing fouling and or sheeting. The amount is generally in theorder of 0.01-0.1 mmol per gram of catalyst composition.

Therefore, the invention also relates to a method for the polymerisationof olefins comprising contacting olefins with the catalyst compositionaccording to the invention in a reactor.

Therefore, in another aspect, the invention relates to a process for thepolymerization of ethylene and optionally one or more alpha-olefinshaving 3 to 10 carbon atoms in a reactor comprising the steps of

-   -   i) adding the ethylene and optionally the one or more        alpha-olefins having 3 to 10 carbon atoms to the reactor and    -   ii) adding the catalyst composition of the invention to the        reactor to produce polyethylene.

Preferably, the invention relates to a process for the polymerization ofethylene and one or more alpha-olefins having 3 to 10 carbon atoms in areactor comprising the steps of

-   -   i) adding the ethylene and optionally the one or more        alpha-olefins having 3 to 10 carbon atoms to the reactor and    -   ii) adding the catalyst composition of the invention to the        reactor to produce linear low density polyethylene.

It has been found that by using the process for the polymerization ofethylene and one or more alpha olefins having 3 to 10 carbon atoms ofthe invention, it is no longer necessary to separately add a reactionproduct of an amine compound and an aluminum compound to the reactor.

Therefore, in a special embodiment, the invention relates to a processfor the polymerization of ethylene and optionally one or morealpha-olefins having 3 to 10 carbon atoms in a reactor comprising thesteps of

-   -   i) adding the ethylene and optionally the one or more        alpha-olefins having 3 to 10 carbon atoms to the reactor and    -   ii) adding the catalyst composition of the invention to the        reactor to produce polyethylene, preferably linear low density        polyethylene, wherein a reaction product of an amine compound,        for example an amine compound of formula (1) with an aluminum        compound, for example an aluminum compound of formula (2) is not        added to the reactor as a separate component.

Surprisingly it has been found that the process for the production ofpolyolefins of the invention leads to less fouling and sheeting in thereactor. Also, the amount of fines in the reactor may be reduced by theprocess for the production of polyolefins of the invention.

Furthermore, it has been found that with the process of the invention,polyolefins, preferably linear low density polyethylene having very goodprocessability can be produced.

Preferably, the polymerization process of the invention is conducted inthe gas-phase.

In another aspect, the invention also relates to linear low densitypolyethylene, obtained or obtainable by polymerization of ethylene andan alpha-olefin having 3 to 10 carbon atoms in a reactor comprising thesteps of

-   -   i) adding the ethylene and the alpha-olefin having 3 to 10        carbon atoms to the reactor and    -   ii) adding the catalyst composition of the invention to the        reactor to produce linear low density polyethylene (LLDPE).

More in particular, the invention relates to linear low densitypolyethylene produced by polymerization of ethylene and an alpha-olefinhaving 3 to 10 carbon atoms in a reactor comprising the steps of

-   -   i) adding the ethylene and the alpha-olefin having 3 to 10        carbon atoms to the reactor and    -   ii) adding the catalyst composition of the invention to the        reactor, preferably a gas phase reactor to produce linear low        density polyethylene (LLDPE),    -   wherein the catalyst composition for the polymerization of        olefins comprises a support containing a single site catalyst        component, preferably a metallocene catalyst, a catalyst        activator, preferably an aluminoxane and a modifier wherein the        modifier is the product of reacting an aluminum compound of        general formula (1)

with an amine compound of general formula (2)

wherein

-   -   R1 is hydrogen or a branched or straight, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R2 and R3 are the same or different and selected from branched        or straight, substituted or unsubstituted hydrocarbon groups        having 1-30 carbon atoms and    -   R4 is hydrogen or a functional group with at least one active        hydrogen    -   R5 is hydrogen or a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R6 is a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,        wherein the catalyst composition is prepared by a method        comprising the steps of

a) preparing the modifier by reacting the aluminium compound of generalformula (1)

with the amine compound of general formula (2)

wherein R1, R2, R3, R4, R5 and R6 are as defined herein

b) activating the single site catalyst component by adding the catalystactivator to said single site catalyst component to obtain an activatedsingle site catalyst component

c) combining in a solvent a support material, the activated single sitecatalyst component obtained in step b) and the modifier obtained in stepa)

d) optionally drying the reaction product obtained in step c)

For example, in an ethylene-alpha olefin copolymer such as linear lowdensity polyethylene (LLDPE), the alpha-olefin having 3 to 10 carbonatoms may be present in an amount of about 5 to about 20 percent byweight of the ethylene-alpha olefin copolymer, for example an amount offrom about 7 to about 15 percent by weight of the ethylene-alpha olefincopolymer.

It has been found that with the process for the production ofpolyolefins of the invention, preferably a gas-phase process, it ispossible to produce linear low density polyethylene having an excellentprocessability.

Therefore, in another aspect, the invention relates to a linear lowdensity polyethylene

-   -   having a density in the range from about 900 kg/m³ to less than        about 940 kg/m³ as determined using ISO1872-2,    -   having a molecular weight distribution (M_(w)/M_(n)) in the        range from 2.5 to 3.5    -   having an area under the peak in the temperature range from 20        to 40° C., for example in the temperature range from 25 to 35°        C., determined using an analytical temperature rising elution        fractionation analysis using 1,2-dichlorobenzene and a heating        rate of 1° C./min, wherein the area is in the range from 5 to        20% of the sum of the areas under all peaks determined with the        analytical temperature rising elution fractionation analysis.

In a different aspect, the invention relates to a linear low densitypolyethylene

-   -   having a density in the range from about 900 kg/m³ to less than        about 940 kg/m³ as determined using ISO1872-2,    -   having a molecular weight distribution (M_(w)/M_(n)) in the        range from 2.5 to 3.5    -   having an area under the peak in the temperature range from 20        to 40° C., for example in the temperature range from 25 to 35°        C., determined using an analytical temperature rising elution        fractionation analysis using 1,2-dichlorobenzene and a heating        rate of 1° C./min, wherein the area is in the range from 5 to        20% of the sum of the areas under all peaks determined with the        analytical temperature rising elution fractionation analysis,        wherein the linear low density polyethylene is produced by a        process of the invention, for example by polymerization of        ethylene and an alpha-olefin having 3 to 10 carbon atoms in a        reactor comprising the steps of

i) adding the ethylene and the alpha-olefin having 3 to 10 carbon atomsto the reactor and

ii) adding the catalyst composition of the invention to the reactor,preferably a gas phase reactor to produce linear low densitypolyethylene (LLDPE)

wherein the catalyst composition for the polymerization of olefinscomprises a support containing a single site catalyst component,preferably a metallocene catalyst, a catalyst activator, preferably analuminoxane and a modifier wherein the modifier is the product ofreacting an aluminum compound of general formula (1)

with an amine compound of general formula (2)

wherein

-   -   R1 is hydrogen or a branched or straight, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R2 and R3 are the same or different and selected from branched        or straight, substituted or unsubstituted hydrocarbon groups        having 1-30 carbon atoms and    -   R4 is hydrogen or a functional group with at least one active        hydrogen    -   R5 is hydrogen or a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,    -   R6 is a branched, straight or cyclic, substituted or        unsubstituted hydrocarbon group having 1-30 carbon atoms,        wherein the catalyst composition is prepared by a method        comprising the steps of

a) preparing the modifier by reacting the aluminium compound of generalformula (1)

with the amine compound of general formula (2)

wherein R1, R2, R3, R4, R5 and R6 are as defined herein

b) activating the single site catalyst component by adding the catalystactivator to said single site catalyst component to obtain an activatedsingle site catalyst component

c) combining in a solvent a support material, the activated single sitecatalyst component obtained in step b) and the modifier obtained in stepa)

d) optionally drying the reaction product obtained in step c)

As used herein, the density of the linear low density polyethylene(LLDPE) is determined using ISO1872-2. For example, the density of theLLDPE may be at least 910, for example at least 915 and/or for exampleat most 940, for example at most 930, for example at most 925, forexample at most 920 kg/m³. For example the density of the LLDPE of theinvention may be in the range from 915 to 925 kg/m³.

As used herein with molecular weight distribution is meant the ratiobetween the weight average molecular weight (Mw) and the number averagemolecular weight (Mn). For purpose of the invention, the Mw and Mn aredetermined using SEC (Size Exclusion Chromatrography using1,2,4-trichlorobenzene as an eluent, and calibrated using linearpolyethylene standards.

For example the molecular weight distribution of the LLDPE of theinvention is at least 2.6, for example at least 2.7, for example atleast 2.8, for example at least 2.9, for example at least 3.0 and/or forexample at most 3.5, for example at most 3.4, for example at most 3.3.For example the molecular weight distribution of the LLDPE of theinvention is in the range from 3.0 to 3.5 or for example in the rangefrom 2.8 to 3.3.

The linear low density polyethylene of the invention preferably has anarea under the peak in the temperature range from 20 to 40° C., forexample in the temperature range from 25 to 35° C., determined using ananalytical temperature rising elution fractionation analysis using1,2-dichlorobenzene and a heating rate of 1° C./min, wherein the area isin the range from 5 to 20% of the sum of the areas under all peaksdetermined with the analytical temperature rising elution fractionationanalysis.

For example, the area under the peak in the temperature range from 20 to40° C. is at least 6%, for example at least 7% and/or for example atmost 18%, for example at most 15%, for example at most 13%, for exampleat most 10%, for example at most 9% of the sum of the areas under allpeaks. For example, the area under the peak in the temperature rangefrom 20 to 40° C. is in the range from 5 to 10% of the sum of the areasunder all peaks.

Preferably, in the LLDPE of the invention, the amount of zirconium (Zr)is in the range from 0.01 to 10 ppm, for example at least 0.1, forexample at least 0.2, for example at least 0.3, for example at least 0.4and/or for example at most 8, for example at most 5, for example at most3, for example at most 1 ppm based on the linear low densitypolyethylene.

Preferably, the LLDPE of the invention substantially does not containchromium, titanium or hafnium, that is the LLDPE of the invention doesnot or only contains what would be considered by the person skilled inthe art, trace amount of chromium, titanium of hafnium, for example lessthan 0.001 ppm.

For purpose of the present invention, the amount of zirconium, chromium,titanium or hafnium is determined using x-ray fluorescence (XRF), whichis calibrated to reference standards. At concentrations below 1 ppm,ICP-MS (Inductively coupled plasma coupled to mass spectrometry) is thepreferred method of determining metal residues present in the LLDPE ofthe invention.

Preferably, the total CH₃ per 1000 carbon atoms as determined using ¹³CNMR is at least 15 and preferably at most 18. The total CH₃ per 1000carbon atoms is a measure for the amount of alpha-olefins having 3 to 10carbon atoms incorporated into the LLDPE.

Preferably, the LLDPE of the invention is a copolymer of ethylene withhexene. The amount of hexene in the LLDPE as determined using ¹³C NMR isfor example at least 7 and at most 10 mol % based on mole ethylene inthe LLDPE.

Preferably, the LLDPE of the invention does not have a reverse comonomercomposition distribution.

A reverse comonomer composition distribution, as used herein, refers toa polymer in which the higher molecular weight components of the polymerhave higher comonomer incorporation than the lower molecular weightcomponents. With reverse comonomer composition distribution, there isincreasing comonomer incorporation with increasing molecular weight. Forpurpose of the invention with reverse comonomer composition distributionis meant that the amount of comonomer incorporation at higher molecularweights is at least more than 10%, for example at least more than 20%higher, for example at least more than 30% higher, than at lowermolecular weights.

Preferably, the LLDPE of the invention also does not have a ZieglerNatta comonomer composition distribution. A Ziegler Natta comonomercomposition distribution, as used herein, refers to a polymer in whichthe lower molecular weight components of the polymer have highercomonomer incorporation than the higher molecular weight components.With Ziegler Natta comonomer composition distribution, there isdecreasing comonomer incorporation with increasing molecular weight. Forpurpose of the invention with Ziegler Natta comonomer compositiondistribution is meant that the amount of comonomer incorporation atlower molecular weights it at least more than 10%, for example at leastmore than 20% higher, for example at least more than 30% higher, than athigher molecular weights.

Preferably, the LLDPE of the invention has homogeneous comonomercomposition distribution. For purpose of the invention with homogeneouscomonomer composition distribution is meant that the comonomerincorporation stays about the same with increasing molecular weight,specifically, that the amount of comonomer incorporation at lowermolecular weights is at most 30%, for example 20%, for example 10%higher than at higher molecular weights and that the amount of comonomerincorporation at higher molecular weights is at most 30%, for example atmost 20%, for example at most 10% higher than at lower molecularweights.

The comonomer composition distribution can be determined using SEC-IR(Size Exclusion Chromatography coupled to an Infrared detector).

Preferably, the linear low density polyethylene of the invention issubstantially free of long chain branching. Substantially free of longchain branching as used herein, refers to a linear low densitypolyethylene substituted with less than 0.1 long chain branching per1000 carbon atoms, more preferably less than 0.01 long chain branchingper 1000 carbon atoms. Most preferably, the linear low densitypolyethylene of the invention is free of long chain branching, that isthe linear low density polyethylene of the invention does not containlong chain branches. As used herein, long chain branching (LCB) isdetermined according to methods known in the art, for example gelpermeation chromatography coupled with low angle laser light scatteringdetector (GPC-LALLS) or with gel permeation chromatography coupled witha different viscometer detector (GPC-DV).

Preferably, the linear low density polyethylene of the invention has amelt flow rate as determined using ASTM D-1238-10, condition E (190° C.,2.16 kg) in the range from 0.5 to 100 dg/min. For example the LLDPE ofthe invention has a melt flow rate in the range from 0.5 to 30 dg/min,for example in the range from 0.5 to 20 dg/min, for example in the rangefrom 0.5 to 5 dg/min, for example in the range from 0.5 to 3.5 dg/min.

Preferably, the LLDPE of the invention has a high load melt index asdetermined using ASTM D-1238-10, condition F (190° C., 21.6 kg) in therange from 10 to 100 dg/min, for example in the range from 10 to 100dg/min, for example in the range from 10 to 40 dg/min, for example inthe range from 15 to 25 dg/min, for example in the range from 16 to 20dg/min.

Preferably, the linear low density polyethylene of the invention has asolubility in hexane as measured using ASTM D5227-01 (2008) of less than5.5 wt %, for example of less than 5 wt %, for example less than 4 wt %,for example less than 3 wt %, for example less than 2.6 wt %, forexample less than 1.5 wt %, for example less than 1 wt %. A lowsolubility in hexane makes the LLDPE of the invention suitable for thepreparation of articles that contact food and, when lower than 2.6 wt %in particular also for articles that are for packing or holding foodduring cooking.

Preferably, the linear low density polyethylene of the invention has acrystallization temperature (T_(c)) in the range from 100 to 140° C. asdetermined using Differential Scanning Calorimetry according to ASTM D3418-08 using a scan rate of 10° C./min on a sample of 10 mg and usingthe second heating cycle, for example a crystallization temperature inthe range from 100 to 120° C.

The invention also relates to a composition comprising linear lowdensity polyethylene of the invention and further comprising additives,for example additives as described herein.

Optionally, additives may be added to the polyolefin, preferably LLDPE,obtained or obtainable by the method of the present invention. Theadditives may for example be added during the melt-mixing. Examples ofsuitable additives include but are not limited to the additives usuallyused for polyethylene, for example antioxidants, nucleating agents, acidscavengers, processing aids, lubricants, surfactants, blowing agents,ultraviolet light absorbers, quenchers, antistatic agents, slip agents,anti-blocking agents, antifogging agents, pigments, dyes and fillers,and cure agents such as peroxides. The additives may be present in thetypically effective amounts well known in the art, such as 0.001 weight% to 10 weight % based on the total composition.

Therefore, the invention also relates to a composition comprising thepolyolefins of the invention and further comprising additives, forexample to a composition consisting of the polyolefin of the inventionand additives.

Therefore, in another aspect, the invention also relates to a processfor the preparation of the composition of the invention furthercomprising the step of

-   -   melt-mixing the polyolefin of the invention and optional        additives.

Before melt-mixing, the polyolefin of the invention and the optionaladditives may be pre-mixed in a mixer, for example a dry blender (as maybe purchased from Henschell). The polyethylene and the additives may bepre-mixed and/or melt-mixed in the form of a powder or granules but mayalso be melt-mixed in the form of pellets.

After the melt-mixing, the composition obtained in the melt-mixing maybe pelletized.

With melt-mixing is meant that the polyolefin and additives are mixed ata temperature that exceeds the Tm or Tc of the polyolefin. Melt-mixingmay be done using techniques known to the skilled person, for example inan extruder, for example a single screw or twin screw extruder,preferably a twin screw extruder.

Suitable conditions for melt-mixing, such as temperature, pressure,amount of shear, screw speed and screw design when an extruder is usedare known to the skilled person.

When using an extruder, a conventional extruder such as a twin-screwextruder may be used. The temperature can vary through the differentzones of the extruder as required. For example, the temperature may varyfrom 180° C. in the feed zone to 300° C. at the die. Preferably, thetemperature in the extruder varies from 165 to 250° C.; likewise, thescrew speed of the extruder may be varied as needed. Typical screwspeeds are in the range from about 100 rpm to about 400 rpm.

The polyolefins of the invention and compositions comprising saidpolyolefins may suitably be used for the manufacture of articles. Forexample, the polyolefins and compositions of the invention may bemanufactured into film, for example by compounding, extrusion, filmblowing or casting and all methods of film formation to achieve, forexample uniaxial or biaxial orientation. Examples of films include blownor cast films formed by coextrusion (to form multilayer films) or bylamination and may be useful as films for packaging, for example asshrink film, cling film, stretch film, sealing films, oriented films,snack packaging, heavy duty bags, grocery sacks, baked and frozen foodpackaging, medical packaging, industrial liners, membranes, etc. infood-contact and non-food contact applications, agricultural films andsheets.

Therefore, the invention also relates to articles comprising polyolefinsof the invention, for example to articles comprising LLDPE of theinvention.

Therefore, in another aspect, the invention also relates to filmscomprising polyolefins of the invention, in particular to filmscomprising LLDPE of the invention or the compositions of the invention.

It has been found that the LLDPE of the invention can suitably be usedfor the preparation of a film having improved optical properties, forexample a low haze and/or a high gloss. Furthermore, the LLDPE of theinvention may also be used for the preparation of a film having improvedhot tack and/or seal strength properties and/or a lower seal initiationtemperature.

Therefore, in another embodiment, the invention relates to a filmcomprising the linear low density polyethylene of the invention or thecomposition of the invention.

Preferably, the film comprises at least 80 wt % of LLDPE of theinvention, for example at least 85 wt %, for example at least 90 wt %,for example at least 95 wt %, for example at least 96 wt %, for exampleat least 97 wt %, for example at least 98 wt %, for example at least 99wt % of the LLDPE of the invention. For example, the film consists ofLLDPE of the invention or of the composition comprising LLDPE andadditives, for example the composition consisting of LLDPE and additivesof the invention.

Preferably, the film according to the invention has a gloss 45° angle asdetermined using ASTM D-2457-08 of at least 50, for example at least 60,for example at least 70, for example at least 75.

Preferably, the film according to the invention has a gloss 60° angle asdetermined using ASTM D-2457-08 of at least 80, for example at least 90,for example at least 100, for example at least 110.

Preferably, the film according to the invention has a haze as determinedusing ASTM D-1003-11 of less than 10, for example of less than 9, forexample of less than 8, for example of less than 7, for example of lessthan 6.

Preferably, the film according to the invention has an average sealstrength as determined using ASTM F88-06 in the temperature range from105 to 140° C. of at least 10N/24 mm, for example at least 10.5N/24 mmand for example at most 15N/24 mm, for example at most 14N/24 mm.

Preferably, the film according to the invention has an average hot tackstrength as determined using ASTM F1912-98 in the temperature range from105 to 120° C. of at least 1.5N/15 mm, for example at least 1.7 N/15 mmand for example at most 4N/15 mm, for example at most 3N/15 mm.

The films of the present invention may be prepared by any method knownin the art, for example by a blown film extrusion process. The thicknessof the film may be chosen in any range, for example in the range of 1 to500 μm, for example in the range from 5 to 100 μm, for example in therange from 20 to 50 μm.

The films of the present invention may be heat sealed to produce anarticle, for example a packaging article. Heat sealing may for examplebe done by sealing equipment such as a compression packaging machine asfor example disclosed in U.S. Pat. No. 3,753,331.

Therefore, in another aspect, the invention relates to an articlecomprising the linear low density polyethylene of the invention, thecomposition of the invention or the film of the invention.

For example, the article, maybe a film that is heat sealed into apackage. In another aspect, the invention relates to the use of the filmaccording to the invention for the preparation of an article, forexample for the preparation of a package In another aspect, theinvention relates to a process for the preparation of a film accordingto the invention, wherein the film is prepared by a blown film extrusionprocess.

Although the invention has been described in detail for purposes ofillustration, it is understood that such detail is solely for thatpurpose and variations can be made therein by those skilled in the artwithout departing from the spirit and scope of the invention as definedin the claims.

It is further noted that the invention relates to all possiblecombinations of features described herein, preferred in particular arethose combinations of features that are present in the claims.

It is further noted that the term ‘comprising’ does not exclude thepresence of other elements. However, it is also to be understood that adescription on a product comprising certain components also discloses aproduct consisting of these components. Similarly, it is also to beunderstood that a description on a process comprising certain steps alsodiscloses a process consisting of these steps.

The invention is now elucidated by way of the following examples,without however being limited thereto.

SHORT DESCRIPTION OF THE FIGURES

FIG. 1 (FIG. 1) shows the aTREF of the LLDPE of comparative example A,wherein T stands for the temperature in ° C. and wherein DD stands forthe differential distribution dC/dT.

FIG. 2 (FIG. 2) shows the aTREF of the LLDPE of comparative example B.In FIG. 2, T stands for the temperature in ° C. and wherein DD standsfor the differential distribution dC/dT.

FIG. 3 (FIG. 3) shows the aTREF of the LLDPE of comparative example C.In FIG. 3, T stands for the temperature in ° C. and wherein DD standsfor the differential distribution dC/dT.

FIG. 4 (FIG. 4) shows the aTREF of the LLDPE of example 11. In FIG. 4, Tstands for the temperature in ° C. and wherein DD stands for thedifferential distribution dC/dT.

FIG. 5 (FIG. 5) shows the seal force SF (N/24 mm) of the LLDPE ofcomparative example A as a function of the temperature T (° C.).

FIG. 6 (FIG. 6) shows the seal force SF (N/24 mm) of the LLDPE ofcomparative example B as a function of the temperature T (° C.).

FIG. 7 (FIG. 7) shows the seal force SF (N/24 mm) of the LLDPE ofcomparative example C as a function of the temperature T (° C.).

FIG. 8 (FIG. 8) shows the seal force SF (N/24 mm) of the LLDPE ofexample 11 as a function of the temperature T (° C.).

FIG. 9 (FIG. 9) shows the hot tack strength HTS (N/15 mm) of the LLDPEof comparative example A as a function of the temperature T (° C.).

FIG. 10 (FIG. 10) shows the hot tack strength HTS (N/15 mm) of the LLDPEof comparative example B as a function of the temperature T (° C.).

FIG. 11 (FIG. 11) shows the hot tack strength HTS (N/15 mm) of the LLDPEof comparative example C as a function of the temperature T (° C.).

FIG. 12 (FIG. 12) shows the hot tack strength HTS (N/15 mm) of the LLDPEof example 11 as a function of the temperature T (° C.).

EXAMPLES Experimental Conditions

All materials were handled in a nitrogen atmosphere using either Schlenktechniques or a nitrogen filled glove box. Nitrogen and isopentane weresupplied from a plant source and were dried through an additional bed ofmolecular sieves, if necessary. All other solvents were first dried overmolecular sieves and if necessary sodium/potassium amalgam. Thecatalysts were prepared using temperature controlled to within 0.5° C.in a silicon oil bath with stirring. Most reagents were used as receivedfrom the manufacturer or supplier.

Example 1 Preparation of Modifiers

Several modifiers according to the invention were prepared as indicatedin Table 1 below.

TABLE 1 AL:N* Modifier molar ratio Description A   1:1 At roomtemperature, add slowly neat 2.47 gram of triisobutylaluminum to asolution of octadecylamine (3.35 gram in 25 ml of isopentane). Removeisopentane under vacuum. The product is high boiling point liquid. B1.6:1 At room temperature, add slowly neat 4.04 gram triisobutylaluminumto a solution of octadecylamine (3.35 gram in 25 ml of isopentane).Remove isopentane under vacuum. The product is high boiling pointliquid. C   3:1 At room temperature, add slowly neat 7.41 gramtriisobutylaluminum to a solution of octadecylamine (3.3490 gram in 25ml of isopentane). Remove isopentane under vacuum. The product is highboiling point liquid. D   1:1 At room temperature, add slowly neat 2.53gram triisobutylaluminum to a solution of 2-ethylhexylamine (1.54 gramin 50 ml of toluene). E   1:1 At room temperature, add slowly neat 0.11ml triisobutylaluminum to a solution of Atmer 163 (0.130 g of Atmer 163in 5 ml of toluene). Atmer 163 is a synthetic ethoxylated amine. *AL:Nmeans molar ratio of aluminum (Al) to nitrogen (N)

Examples 2-4

In Examples 2-4 several catalyst compositions were tested.

0.0880 gram of metallocene catalyst component biphenyl(2-indenyl)₂ZrCl₂was activated separately by adding to the catalyst component 10.7 ml ofMAO (10 wt % solution in toluene). In a reaction flask, 10 ml of toluenewas added to 5 gram of silica (Grace 955 obtained from Aldrich ChemicalCo.) as a support. The activated catalyst component was then transferredto the silica support and the mixture was allowed to react at atemperature of about 50° C. for 1 hour.

A modifier was then added to the reaction mixture, after which reactionwas allowed to continue for 30 minutes followed by vacuum drying of thecatalyst composition. The catalyst compositions contained 0.244 wt % ofZr and 7.2 wt % of Al (originating from the MAO; additional Al contentoriginating from the modifier not included). This resulted in a molarratio of Al/Zr of about 100.

Flow properties of the dry catalyst composition were judged visually.

The catalyst composition was tested in an ethylene slurryhomopolymerisation process. Productivity in terms of gram PE per gramcatalyst composition was determined and after the reaction the reactorwas inspected for fouling and/or sheeting.

The results can be found in Table 2 below.

TABLE 2 Fouling/ Productivity [gram Ex. Modifier Flowability sheetingPE/gram Cat.] 2 Modifier A Excellent None 6500 0.195 gram in 5 mltoluene 3 Modifier B Excellent None 3783 0.195 gram in 5 ml toluene 4Modifier C Excellent None 2967 0.195 gram in 5 ml toluene

Example 5

Example 5 is similar to Examples 2-4.

4.380 gram of metallocene catalyst component biphenyl(2-indenyl)₂ZrCl₂was activated separately by adding to the catalyst component 531 ml ofMAO (10 wt % solution in toluene). In a reaction vessel, 600 ml oftoluene was added to 250 gram of silica (Grace 955 obtained from AldrichChemical Co.) as a support. The activated catalyst component was thentransferred to the silica support and the mixture was allowed to reactwhile being stirred at a temperature of about 50° C. for 1 hour.

The solution of modifier D above was then added to the reaction mixture,after which reaction was allowed to continue for 30 minutes followed byvacuum drying of the catalyst composition. The catalyst compositioncontained 0.24 wt % of Zr and 7.2 wt % of Al (originating from the MAO;additional Al content originating from the modifier not included). Thisresulted in a molar ratio of Al/Zr of about 100. The flowability of thiscatalyst was excellent. No reactor sheeting or fouling was observed andthe productivity was 2050 gram PE/gram catalyst.

Examples 6-8 Fluid-Bed Polymerisation

The supported catalyst of Examples 2-4 of Table 4 were tested in acontinuous gas phase fluidized bed reactor having an internal diameterof 45 cm and a reaction zone height of 140 cm. The bed of polymerparticles in the reaction zone is kept in a fluidized state by a recyclestream that works as a fluidizing medium as well as a heat dissipatingagent for absorbing the exothermal heat generated within reaction zone.The reactor was kept at a constant temperature of about 87° C. and at aconstant pressure of about 21.7 bar. Ethylene and hexene were used asthe raw materials for polymerisation. These materials form a make-upstream. A Continuity Aid Agent (CAA) was mixed with the make-up streamas a 2% by weight solution in isopentane carrier solvent. The catalystcomposition contained biphenyl(2-indenyl)₂ZrCl₂ as the catalystcomponent.

The solid catalyst composition was injected directly in the reactionzone of the fluidized bed using purified nitrogen as a carrier gas. Theinjection rate was adjusted to maintain a constant production rate ofabout 12 kg/hr. The produced polymer was discharged from the reactionzone semi-continuously via a series of valves into a fixed volumechamber. The so obtained product was purged to remove any volatilehydrocarbons and was then treated with humidified nitrogen to deactivateany trace quantities of residual catalyst composition. The properties ofthe polymer were determined by the following test methods:

TABLE 3 Melt Index ASTM D-1238-10 Condition E (190° C., 2.16 kg) MeltIndex ASTM D-1238-10 Condition F (190° C., 21.6 kg) Density ISO1872-2.The samples were prepared and pressed according to ISO1872-2 andannealed by boiling in water for half an hour, then left to cool for 16hours in the same water after which the samples were measured. Bulk Theresin is poured in a fixed volume cylinder of 400 Density cc. The bulkdensity is measured as the weight of resin divided by 400 cc to give avalue in g/cc. Average The particle size is measured by determining theParticle weight of material collected on a series of U.S. Size Standardsieves and determining the weight average particle size based on thesieve series used. Fines fines are defined as the percentage of thetotal distribution passing through a 120 mesh standard sieve. This has aparticle size equivalent of 120 microns. Tm Tm is determined accordingto ASTM D3418-08 as follows: Samples weighing approximately 5-10 mg aresealed in aluminum sample pans. The DSC data is recorded by firstcooling the sample to −50° C. and then gradually heating it to 200° C.at a rate of 10° C./min. The sample is kept at 200° C. for 5 minutesbefore a second cooling-heating cycle is applied. Both the first andsecond cycle thermal events are recorded. The melting temperature ismeasured and reported during the second heating cycle (or second melt).Solubility ASTM D5227-01(2008). Film samples are extracted in hexanewith hexane for 2 hours at 49.5° C. ± 0.5° C., dried and weighed. Theloss in weight of the film is the solubility in hexane. Molecular Samplepreparation weight The polymer samples were dissolved (0.1 w %) indistribution 1,2,4-trichlorobenzene (TCB), which was distilled (Mw/Mn)prior to use, over a period of 4 h at 150° C. under nitrogen andstabilized with di-tertbutylparacresol (DBPC) at a concentration of 1g/L. The solutions were filtered at high temperature (150° C.) using amillipore filtration setup (1.2 μm) positioned in a Hereous LUT ovenoperating at 150° C. SEC-DV measurement The separation of the polymeraccording to molar mass is performed with a PL-GPC220 equipped with PLBV-400 viscosimeter and refractive index detector. This SEC system isoperated at high temperature (column compartment at 150° C., injectorcompartment at 150° C., and solvent reservoir at 60° C.) and a flow of1.0 mL/min. Four Polymer Laboratories GPC columns (PL 13 μm mixed Olexiscolumns) were used. Calculations were performed with Viscotek TriSEC 2.7software. The eluent used was 1,2,4-trichlorobenzene. The columns werecalibrated using linear polyethylene standards.

TABLE 4 Example 6 7 8 Zr (wt %) 0.18 0.20 0.24 Ethylene (mole %) 46.046.0 46.0 Hexene (mole %) 5.29 5.25 5.22 Continuity Aid Agent (ppm) 5050 50 Catalyst Productivity (kg/kg) 5,870 6,050 6,700 Residual Ash (ppm)155 150 140 Melt Index-MI (dg/min) 1.03 1.02 0.99 Density (g/cc) 0.91900.9187 0.9183 Bulk Density (g/cc) 0.372 0.375 0.377 Average ParticleSize (microns) 860 895 938 Fines (%) 0.1 0.1 0.1

As can be seen from the results presented in Table 4, polyolefins suchas LLDPE can be produced with the catalyst composition of the inventionwith a minimal amount of fines, which means that fouling and/or sheetingin gas phase and slurry polymerization processes will also be minimal.

Example 9 Large Scale Preparation of the Catalyst Composition of theInvention

At room temperature, 0.595 kg of diphenyl(2-indenyl)₂ZrCl₂ was added to36.968 kg of a 30% methylaluminoxane solution (Al content 13.58 wt %)and stirred for 30 minutes to form activated metallocene. About 172 kgof dry toluene was added to 43 kg of silica 955 to form a silica slurry.At about 30° C., the activated metallocene was added to the silicaslurry under agitation. After the activated metallocene was added, thetemperature was increased to 50° C. After 2 hours at 50° C., all ofmodifier F (Table 5) was added. After addition the mixture was kept at50° C. for 1 hour. The reaction temperature was then reduced to 30° C.The toluene was removed by filtration and the obtained catalystscomposition was dried by raising the temperature to 55° C. and using aflow of warm nitrogen. The Al/Zr ratio used in this experiment wasapproximately 150.

TABLE 5 Modifier F At room temperature, add slowly 0.114 kg of neattriisobutylaluminum to a solution of 0.057 kg of cyclohexylamine in 9.7kg of dry toluene.

The catalyst composition obtained had an excellent flow as judgedvisually.

Example 10

The catalyst composition was tested in an ethylene slurry polymerisationprocess. After the reaction, the reactor was inspected for foulingand/or sheeting and no fouling/sheeting was observed.

Example 11

Also, the properties of the polymer prepared were tested using themethods as indicated herein.

The properties were compared to the properties of other linear lowdensity polyethylenes.

Comparative Example A: LLDPE 6118NE from Saudi Basic IndustriesCorporation Comparative Example B: LLDPE Exceed® 1018CA (Lot: M07120316C(USA)) from Exxon Mobile Comparative Example C: LLDPE Eltex® PF6212LAfrom Ineos Polyolefins Example 11: LLDPE Produced in Example 10; ExampleAccording to the Invention

The properties of the materials are indicated in Table 6 below:

TABLE 6 LLDPEs used and their properties. Ex MI_(2.16) D Cat. LCBComonomer incorporation A 0.84 921.4 ZN No 1-hexene Ziegler Natta B 0.9920.1 M No 1-hexene homogeneous C 1.34 919.5 M Yes 1-hexene reverse 110.99 920.5 M No 1-hexene homogeneous MI_(2.16): melt flow index,measured according to ASTM D-1238-10 Condition E (190° C. 2.16 kg) indg/min D: density (kg/m³) Cat: catalyst LCB: long chain branching ZN:Ziegler Natta M: Metallocene incorporation: the comonomer compositiondistribution, that is the distribution of the short chain branching(butyl branches due to incorporation of the 1-hexene comonomer) as afunction of the molecular weight.

TABLE 7 Properties of LLDPE produced in example 11 (modifier F) comparedto comparative examples Example/property A B C 11 Density (kg/m³) 921.4920.1 919.5 920.5 M_(w)/M_(n) 4.6 2.6 4.2 3.2 Zr <0.01 <0.01 0.1-1 TotalCH₃ 16.7 12.5 16.1 16.8 per 1000 carbon atoms Butyl branches (hexane)16.0 (9.6) 12.0 (7.3) 15.2 (8.3) 16.1 (9.4) per 1000 C (wt %) Melt flowrate (190° C., 0.84 0.9 1.34 0.99 2.16 kg) Solubility in hexane (wt %)<0.6 <1.0 Crystallization temp. (° C.) 66 67 64 68 (main peak at higher111.2 106.0 104.8 109.7 temperature)

An analytical temperature rising elution fractionation (aTREF) wasperformed on the examples of comparative examples A-C and of example 11.

Analytical temperature rising elution fractionation (ATREF) analysis wasconducted according to the method described in U.S. Pat. No. 4,798,081and Wilde, L.; Ryle, T. R.; Knobeloch, D. C; Peat, L R.; Determinationof Branching Distributions in Polyethylene and Ethylene Copolymers, J.Polym. ScL, 20, 441-455 (1982), which are incorporated by referenceherein in their entirety. The composition to be analyzed was dissolvedin 1,2-dichlorobenzene of analytical quality filtrated via 0.2 μm filterand allowed to crystallize in a column containing an inert support(Column filled with 150 μm stainless steel beans (volume 2500 μL) byslowly reducing the temperature to 20° C. at a cooling rate of 0.1°C./min. The column was equipped with an infrared detector. An ATREFchromatogram curve was then generated by eluting the crystallizedpolymer sample from the column by slowly increasing the temperature ofthe eluting solvent (1,2-dichlorobenzene) from 20 to 130° C. at a rateof 1° C./min.

The instrument used was Polymer Char Crystaf-TREF 300.

Stabilizers: 1 g/L Topanol+1 g/L Irgafos 168

Sample: approx. 70 mg in 20 mL

Sample volume: 0.3 mL

Pump flow: 0.50 mL/min

The software from the Polymer Char Crystaf-TREF-300 was used to generatethe spectra.

The results are presented in FIGS. 1-4 and in Table 8 below. In Table 8,the peak temperature of the peaks is indicated with the area as apercentage of the sum of the areas under all peaks determined withaTREF.

TABLE 8 Ex. Peak 1: Peak 2: Peak 3: A 97.8° C./51.4% 79.9° C./35.4% 35°C./13.1% B 94.4° C./24.5% 84.5/75.1% 35° C./~0.5% C 95.1/20.9%78.1/77.7%   35° C./1.4% 11 96.8° C./46.5% 83.3° C./46.0%  35° C./7.5%

As can be seen from Table 8, the LLDPE according to the invention has anarea under the peak in the temperature range from 20 to 40° C., forexample in the temperature range from 25 to 35° C., determined using ananalytical temperature rising elution fractionation analysis using1,2-dichlorobenzene and a heating rate of 1° C./min, wherein the area isin the range from 5 to 20% of the sum of the areas under all peaksdetermined with the analytical temperature rising elution fractionationanalysis

Example 11

Preparation of Film

The LLDPE powder produced in example 10 was melt-mixed with suitableadditives in a twin screw extruder to produce LLDPE pellets. It wasfound that the LLDPE powder had a very good processability.

Single layer films of 25 μm were produced from the LLDPE pellets on aBrabender blown film line, having a frost line height of 30 cm using ablow up ratio of 2.5 and a die thoughput of 3.0 kg/hr/cm. (output 60kg/h)

The line was equipped with a Ø 200 mm die, a die gap of 2.3 mm,reversing haul-off, chilled cooling air, thickness profile measurementand back to back winder. The overall throughput was kept constant.Barrel temperature profiles were ramped from 170° C. at the feed sectionto 200° C. at the die.

The properties of the film were measured according to the methodsmentioned in Table 9.

TABLE 9 Property Measurement method Gloss 45° angle and Gloss 60° angleASTM D-2457-08 Haze ASTM D-1003-11 Hot tack strength ASTM F1912-98 Sealforce ASTM F88-06

The example was repeated for the LLDPEs of comparative examples A-C.

It was found that the LLDPE of the invention showed a betterprocessability in the extruder as compared to comparative examples A-C.

The results for the gloss and haze are given in Table 10 below.

TABLE 10 Gloss and haze of single layer films of 25 μm of comparativeexamples A-C and of example 11. Example/property A B C 11 Gloss 45°angle 38.9 67 64.7 76.3 Gloss 60° angle 76.2 122.4 Haze 12.9 5.1

As can be seen from Table 10, film comprising LLDPE of the invention hasexcellent optical properties (high gloss and low haze). The results forthe seal force and hot tack strength of the films are given in FIG.5-FIG. 12.

As can be seen by comparing FIG. 8 with FIG. 5-7, film of the inventionshows a considerably higher average seal force (also referred to hereinas seal strength) in the temperature range from 105 to 140° C. ascompared to the films comprising the LLDPE of the comparative examplesA-C.

As can be seen by comparing FIG. 12 with FIG. 9-11, film of theinvention shows a considerably higher average hot tack strength in thetemperature range from 105 to 120° C. as compared to the filmscomprising the LLDPE of the comparative examples A-C.

The invention claimed is:
 1. A catalyst composition for thepolymerisation of olefins comprising a support; a single site catalystcomponent; a catalyst activator; and a modifier wherein the modifier isthe product of reacting an aluminum compound of general formula (1)

with an amine compound of general formula (2)

wherein R1 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms, R2 and R3 arethe same or different and selected from branched or straight,substituted or unsubstituted hydrocarbon groups having 1-30 carbonatoms, R4 is hydrogen or a functional group with at least one activehydrogen, R5 is hydrogen or a branched, straight or cyclic, substitutedor unsubstituted hydrocarbon group having 1-30 carbon atoms, R6 is abranched, straight or cyclic, substituted or unsubstituted hydrocarbongroup having 1-30 carbon atoms, wherein the single site catalystcomponent, the catalyst activator, and the modifier are all present onthe support; and wherein the aluminum content of the catalystcomposition is in the range of 3-20 wt % based on the total weight ofthe catalyst composition.
 2. The catalyst composition according to claim1 wherein the amine compound is selected from octadecylamine,ethylhexylamine, cyclohexylamine, bis(4-aminocyclohexyl)methane,hexamethylenediamine, 1,3-benzenedimethanamine,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane and6-amino-1,3-dimethyluracil.
 3. The catalyst composition according toclaim 1, wherein the aluminum compound is a tri-alkylaluminum compound.4. The catalyst composition according to claim 1, wherein the amounts ofaluminum compound and amine compound are selected such that in themodifier a molar ratio of Al to N is in the range of 1:3 to 5:1.
 5. Thecatalyst composition according to claim 1, wherein the catalystactivator is an alumoxane, a perfluorophenylborane, aperfluorophenylborate or a mixture of at least two of such catalystactivators.
 6. The catalyst composition according to claim 1, whereinthe composition further comprises a Ziegler-Natta and/or a chromiumbased catalyst component.
 7. The catalyst composition according to claim1, wherein the aluminum content of the catalyst composition is in therange of 7-12 wt %, based on the total weight of the catalystcomposition.
 8. The catalyst composition according to claim 1, whereinthe single site catalyst component is a metallocene catalyst.
 9. Thecatalyst composition according to claim 8 wherein the metallocenecatalyst contains zirconium and wherein the zirconium content of thecatalyst composition is in the range of 0.02-1 wt % based on thecatalyst composition.
 10. A method for preparing the catalystcomposition according to claim 1 comprising: a) preparing a modifier byreacting an aluminum compound of general formula (1)

with an amine compound of general formula (2)

b) activating a single site catalyst component by adding a catalystactivator to said single site catalyst component to obtain an activatedsingle site catalyst component; c) combining in a solvent a supportmaterial, the activated single site catalyst component obtained in stepb) and the modifier obtained in step a); d) optionally drying thereaction product obtained in step c); wherein R1 is hydrogen or abranched or straight, substituted or unsubstituted hydrocarbon grouphaving 1-30 carbon atoms, R2 and R3 are the same or different andselected from branched or straight, substituted or unsubstitutedhydrocarbon groups having 1-30 carbon atoms, R4 is hydrogen or afunctional group with at least one active hydrogen, R5 is hydrogen or abranched, straight or cyclic, substituted or unsubstituted hydrocarbongroup having 1-30 carbon atoms, and R6 is a branched, straight orcyclic, substituted or unsubstituted hydrocarbon group having 1-30carbon atoms.
 11. The method according to claim 10 wherein step a) iscarried out at a temperature of 0° C.-50° C.
 12. A method for thepolymerisation of olefins comprising contacting olefins with thecatalyst composition according to claim 1 in a reactor.
 13. A methodaccording to claim 12 comprising i) adding ethylene and optionally oneor more alpha-olefins having 3 to 10 carbon atoms to the reactor; andii) adding the catalyst composition to the reactor to produce apolyethylene.
 14. The method for polymerisation of olefins according toclaim 12 wherein during the polymerisation a continuity aid agent isadded to the reactor wherein said continuity aid agent is preparedseparately prior to introduction into the reactor by reacting: at leastone metal alkyl or metal alkyl hydride compound of a metal from groupIIA or IlIA of the periodic system of elements, and at least onecompound of general formula R_(m)XR′_(n′) wherein R is a branched,straight, or cyclic, substituted or unsubstituted hydrocarbon grouphaving 1 to 50, R′ is hydrogen or a functional group with at least oneactive hydrogen, X is a heteroatom selected from the group of O, N, P orS, n and m are each at least 1 and are such that the formula has no netcharge, and the molar ratio of the metal of the metal alkyl compound andX is about 2:1 about 10:1.
 15. The method for polymerisation of olefinsaccording to claim 14, wherein the continuity aid agent is the productof reacting an aluminum compound of general formula

with an amine compound of general formula

wherein R1 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms, R2 and R3 arethe same or different and selected from branched or straight,substituted or unsubstituted hydrocarbon groups having 1-30 carbonatoms, R4 is hydrogen or a functional group with at least one activehydrogen, R5 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms, R6 is abranched or straight, substituted or unsubstituted hydrocarbon grouphaving 1-30 carbon atoms.
 16. A method of reducing reactor fouling,reactor sheeting, or a combination thereof during polymerization ofolefins, the method comprising: polymerizing olefins in the presence ofa catalyst composition; wherein the catalyst composition comprises asupport, a single site catalyst component, a catalyst activator, and amodifier; wherein the modifier comprises a reaction product obtained byreacting an aluminum compound of general formula

with an amine compound of general formula

wherein R1 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms, R2 and R3 arethe same or different and selected from branched or straight,substituted or unsubstituted hydrocarbon groups having 1-30 carbonatoms, R4 is hydrogen or a functional group with at least one activehydrogen R5 is hydrogen or a branched or straight, substituted orunsubstituted hydrocarbon group having 1-30 carbon atoms, and R6 is abranched or straight, substituted or unsubstituted hydrocarbon grouphaving 1-30 carbon atoms; wherein the single catalyst component, thecatalyst activator, and the modifier are all present on the support; andwherein the aluminum content of the catalyst composition is in the rangeof 3-20 wt % based on the total weight of the composition.
 17. Thecatalyst composition of claim 1, wherein the composition is a powdercomprising particles having a size of 1 to 300 microns.
 18. The methodof claim 13, wherein the polyethylene is a linear low densitypolyethylene.